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Summary: The immune system plays a critical role in protecting the host against infection but is subject to numerous levels of control that are necessary to prevent pathological, tissue-damaging responses. Inappropriate inflammatory immune responses to self-antigens, innocuous commensal microorganisms, or environmental antigens can lead to chronic, debilitating, and degenerative diseases. Regulatory T cells have an essential, non-redundant, and dominant function in preventing pathological immune responses, as shown by the development of systemic fatal autoimmunity in humans and animals with a genetic deficiency in regulatory T cells. In addition to controlling immune responses, there is a growing understanding that regulatory T cells also contribute directly to tissue homeostasis by promoting tissue regeneration and repair. For these reasons, the prospect of enhancing regulatory T-cell numbers and/or function in patients represents an appealing therapeutic opportunity with potential applications in many diseases, including some where the pathological role of the immune system has only recently been recognized. Approaches to enhance regulatory T cells are now starting to be explored in clinical studies in humans. This review series brings together papers highlighting the Treg-enhancing approaches that are most advanced clinically and examples of therapeutic opportunities based on our growing understanding of regulatory T-cell functions. [ABSTRACT FROM AUTHOR]

Recent research has characterized the behavioral defense against disease. In particular the detection of sickness cues, the adaptive reactions (e.g. avoidance) to these cues and the mediating role of disgust have been the focus. A presumably important but less investigated part of a behavioral defense is the immune system response of the observer of sickness cues. Odors are intimately connected to disease and disgust, and research has shown how olfaction conveys sickness cues in both animals and humans. This study aims to test whether odorous sickness cues (i.e. disgusting odors) can trigger a preparatory immune response in humans. We show that subjective and objective disgust measures, as well as TNFα levels in saliva increased immediately after exposure to disgusting odors in a sample of 36 individuals. Altogether, these results suggest a collaboration between behavioral mechanisms of pathogen avoidance in olfaction, mediated by the emotion of disgust, and mechanisms of pathogen elimination facilitated by inflammatory mediators. Disgusting stimuli are associated with an increased risk of infection. We here test whether disgusting odors, can trigger an immune response in the oral cavity. The results indicate an increase level of TNFα in the saliva. This supports that disease cues can trigger a preparatory response in the oral cavity. [ABSTRACT FROM AUTHOR]

Controlling oxidative stress in shrimps under culture conditions is of vital importance to ensure that males have an optimal physiological status. The use of diets supplemented with vitamins are widely used for this purpose. We evaluated the effects of vitamin C on the metabolic, antioxidant, and immune responses of Penaeus brasiliensis Latreille, 1817 broodstock males under culture conditions. A formulated diet was used as a control (16 mg kg–1 of total ascorbic acid (vitamin C) content) and three diets were prepared with three vitamin C levels: 322 mg kg–1 (Diet A), 628 mg kg–1 (Diet B), and 934 mg kg–1 (Diet C). Triglycerides, cholesterol, glucose, and prophenoloxidase, total proteins, and quantity and type of hemocytes in the hemolymph were determined. We also quantified the antioxidant enzyme activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (Gpx) and lipid peroxidation in the reproductive tract. Differentially expressed genes of the immune system, namely those of α-2 macroglobulin (α2M), peneidin (Pen), hemocyanin, prophenoloxidase, and the genes encoding the antioxidant enzymes SOD, CAT, and Gpx were quantified in the tract. Sperm quantity and quality were recorded. In males fed Diet C, the lowest cholesterol values and triglycerides obtained in the hemolymph were not significantly different from those fed the control diet (P < 0.05); those fed Diet C showed the highest amount of hyaline hemocytes, the lowest CAT enzyme activity, and the highest Gpx activity. The immune system genes only showed differences between α2M and Pen; sperm quantity and quality were not affected by diet. The results indicated that Diet C (13.9 g kg–1 vitamin C) was effective for the maintenance of P. brasiliensis broodstock males because it controlled cholesterol and triglyceride levels; there was less CAT activity and less activation of the immune system mediated by hemocytes. [ABSTRACT FROM AUTHOR]

The human gut microbiome interacts with each other and the host, which has significant effects on health and disease development. Intestinal homeostasis and inflammation are maintained by the dynamic interactions between gut microbiota and the innate and adaptive immune systems. Numerous metabolic products produced by the gut microbiota play a role in mediating cross‐talk between gut epithelial and immune cells. In the event of an imbalance between the immune system and microbiota, the body becomes susceptible to infections and homeostasis is compromised. This review mainly focuses on the interplay between microbes and the immune system, such as T‐cell‐ and B‐cell‐mediated adaptive responses to microbiota and signalling pathways for effective communication between the two. We have also highlighted the role of microbes in the activation of the immune response, the development of memory cells and how the immune system determines the diversity of human gut microbiota. The review also explains the relationship of commensal microbiota and their relation to the production of immunoglobulins. [ABSTRACT FROM AUTHOR]